Witch's Knoll (魔女の丘, Majo no Oka?) "Witch Hill" in Funimation's subs) is a sunflower field located in the Human World near Tsukune's hometown that is rumored by tourists to be inhabited by witches.
Tsukune and the group stopped here on request from the bus driver, who wanted them to investigate the reason behind the tourists' disappearances.